Design Considerations in Multi-area OSPF
The major design consideration in OSPF is how to divide the areas. This is of interest because it impacts the addressing scheme for IP within the network. In designing a network, consider the resources available and make sure that none of these resources are overwhelmed, either initially or in the future. In the creation of areas, OSPF has tried to provide the means by which the network can grow without exceeding the available resources. In an OSPF network, su..
KEEPALIVE messages are comprised only of the 19-byte BGP message header shown in Figure 11-3. These are exchanged whenever an update-free period exceeds the holdtime negotiated in the OPEN message exchange. A KEEPALIVE is also sent to acknowledge the OPEN message before moving from the OPEN_SENT to ESTABLISHED session state. If the holdtime is zero, KEEPALIVE messages are not sent, except to acknowledge an OPEN. TIP The minimum keepalive period is ..
Single-Rate, Two-Color Policing (One Bucket)
Single-rate, two-color policing is the simplest option for CB Policing. This method uses a single policing rate with no excess burst. The policer will then use only two categories (conform and exceed), defining a different action on packets of each type. (Typically, the conform action is to transmit the packet, with the exceed action either being to drop the packet or mark it down.) While this type of policing logic is often called single-rate, two-color policing, it is some..
Filtering by Source or Destination IP Address
You can use standard access-lists to block packets from specified IP source addresses: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router1(config)#access-list 50 deny host 10.2.2.2 Router1(config)#access-list 50 permit any Router1(config)#interface Serial0/1 Router1(config-if)#ip access-group 50 in Router1(config-if)#exit Router1(config)#end Router1# You can filter packets based on both the source and destination addresses w..
The value proposition of a network is that it ties together different entities and enables exchange of information. The network's value is also directly related to its size. The more entities that are connected and partake in the network, the higher the impact of the network is. For exchange and scaling to occur in a relevant and orderly manner, the connected entities must use the same language. As such, standards form an integral component of networks because they enforce or..
